Major advances in plant transformation have occurred over the last few years. However, in major crop plants, such as maize and soybeans, serious genotype limitations still exist. Transformation of agronomically important rice cultivars (and a small number of maize inbreds) has reached workable levels using either particle bombardment or Agrobacterium to deliver DNA. However, losses in efficiency occur due to reductions in embryogenecity and subsequent regeneration. Traditionally, embryogenecity and regeneration were improved by optimizing medium components and/or explant material and source. This led to success, but improvements are still needed to make the process more efficient and less time consuming. Therefore it would be desirable to provide improved methods capable of increasing transformation efficiency, stimulating embryogenic growth in culture and improving regeneration of vigorous, fertile plants.